The prayer known as the Guardian's Mantra was uttered by individuals belonging to the Guardians of the Whills, protectors of the Temple of the Kyber situated in Jedha City on the planet Jedha, and Jedi also used this mantra. Penned by an author whose identity remains unknown, the Mantra was discovered within Collected Poems, Prayers, and Meditations on the Force, a compilation edited by Kozem Pel, a Disciple of the Whills. It was recited when guidance from the Force was sought.
The Mantra's origins trace back to ancient times, specifically before 382 BBY, a year that falls within the High Republic Era. During this period, Matthea Cathley, a Jedi Padawan stationed on the moon of Jedha for her training, learned the Guardian's Mantra from the Guardians of the Whills. In 382 BBY, as Cathley ventured into the Path compound just before the Battle of Dalna erupted, she repeated the mantra to soothe her anxiety. Following an encounter with the terrifying Nameless, she shared the mantra with Azlin Rell, a frightened Jedi Knight, encouraging him to recite it alongside her. However, as they passed more corpses, Rell's words devolved into muttering about how "they" had emerged and would return.
After the implementation of Order 66 in 19 BBY, Ahsoka Tano, a former Jedi Padawan fleeing mind-controlled clone troopers aboard the Venator-class Star Destroyer Tribunal while in hyperspace, recited a portion of the Guardian's Mantra. She used the Force to locate the control chip within the head of her friend, Clone Commander Rex, with the intention of removing it. Despite being unconscious, Rex began to repeat the mantra along with Tano as she performed this action.
Chirrut Îmwe and Baze Malbus, Guardians of the Whills who died while assisting in the theft of the plans for the Death Star during the Battle of Scarif, both uttered the Mantra in their last moments.
The initial appearance of the Guardian's Mantra was in the 2016 film, Rogue One: A Star Wars Story. Its identification by name occurred in the junior novel Guardians of the Whills.